Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8ac31baa4e9e859fa62494ae6873e1a1ee73c5da8c13ddc87b1af3a85e47f21' 
  AND token = '1TI8N8SdVFmYHsqwUHC7s2MDLJbDhjYC6pPSbeLzsWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}